It is well known that personality and emotions can influence coronary events, and in turn affect mortality. A number of studies have shown a significant correlation between clinical depression and subsequent coronary events. The exact mechanisms underlying this association are however not well characterized. Emerging data has strongly implicated endothelial dysfunction as an important predictor of adverse vascular events. There are a variety of reasons to suspect that endothelial function may be abnormal in depressed patients This include abnormalities in the hypothalamic-pituitary system, sympathoadrenal system and recent data suggesting immune activation. In this study we hope to provide preliminary data demonstrating a link between depression and abnormal vascular reactivity. Further we also hope to provide some mechanistic insights by showing a significant correlation between endothelial dysfunction and cytokine activation in depression.